Compressor unloader



April 14, 1936.

COMPRESSOR UNLOADER Filed Nov. 1'7, 1933 INVEYNTOR.

165 Nazi/2.911

W ATroklJEv E. NATHAN 2,037,140

Patented Apr. 14, 1936 PATENT OFFICE 2,037,140 COMPRESSOR UNLOADER Ellis Nathan; Easton, Pa., assignor to Pennsylvania Pump & Compressor 00., Easton, Pa., a

corporation of Ifennsylvania.

Application November 17, 1933, Serial No. 698,386

2 Claims.

This invention relates to compressors for air and other gases and in particular to an unloading device for a single acting double cylinder air or gas compressor. 7

A primary object of the present invention is to provide a simple form of unloader adapted to simultaneously unload the cylinders of a compressor having adjacent single acting pistons by movement of a single valve contacting member. 10 One feature which enables me to accomplish the above mentioned object is that a member is provided having fingers engaging the intake valves of the adjacent cylinders, this member being moved to engage or disengage the intake 15 valves by a pressure responsive device.

With the above and other objects in view, my invention includes the features of construction and operation set forth in the following specification and illustrated in the accompanying 20 drawing.

In theacc ompanying drawing annexed hereto and forminga part of this specification, I have shown my invention embodied in a small size air compressor having single acting pistons in adjacent parallel cylinders, butit will be understood that the invention can be otherwise embodied and that the drawing is not to be. con-,

strued as defining or limiting the scope of the invention, theclaims appended to this specifl- 30 cation being relied upon for that purpose.

In the drawing the figure is a vertical sectional view of a complete compressor provided with the novel unloading means. 2

In the above mentioned drawing I have shown 35 but one embodiment of the invention which is now deemed preferable, but it is to be understood that changes and modifications may be made within the scope of the appended claims without departing from the spirit of theinvention.

Briefly, and in its broadest aspect, my invention may include the following principal parts: First, a compressor cylinder casing having adjacent parallel cylinder openings therein; sec- 45 0nd, a cylinder head secured to said casing; third, discharge valves secured within said head and connecting the space within each cylinder with discharge passages; fourth,.in1et valves contacting with said intake valves, and means to move said member to render said intake valves operative or inoperative.

Referring more in detail to the figure of the drawing, I provide a cylinder casing i0 within which are provided parallel'cyllnder openings ll. Supporting the casing I0 is a base It having a main crank shaft l4 extending therethrough and driven by any suitable source of power atone end. Within the openings ll operate pistons i3 shown as of trunk form connected to the main crank shaft I4 by connecting rods l5 of standard or conventional type. It will be noted that the pistons are single acting and compress air or gas by admitting and discharging the air or 7 gas to and from one end only.

Secured to the end of.- the easing opposite that to which the base l2 isz-secured is a cylinder head it within which are-mounted discharge valves l9 one being shown for each cylinder. These 0 discharge valves ill have their assemblies retained in place against a recessed seat in the cylinder head I8 by-a clamping screw threaded through a small valve cover 2! above the valve l9 and secured by any appropriate means (not shown) to the cylinder head It. As the discharge valves and their assemblies and, retaining means form no part of the present invention and are or may be of old and well-known types, further description is not thought to be necessary. The space above the valves l9 and within the cylinder head It forms a discharge passage 22 for the compressed gases delivered from both cylinders. This space 22 is in the form of an annulus, the inner periphery or wall of which is formed by a partition 23 forming an integral part of thecylinder head or cover plate is. In the outer wall of this annulus a discharge pipe of any type (not shown) may be connected by means of an opening 45 the surface of which may be suitably threaded.

Secured also within recessed openings in the cover plate or cylinder head l8 are intake valves 25, one being shown for each of the cylinders. These intake valves 25 are old and well-known so. that a description will be unnecessary. These valves are mounted within the circular partition or wall 23 forming an integral part of the head i8 and separating the discharge space 22 from the space within the wall 23 to which air to be compressed is admitted. To retain the assemblies for the intake valves 25 in position clamping members 25 are provided. One of these members 26 is provided for each intake valve 25. These'members 26 are in the form of short hollow cylinders,

the intake valves 25 and the cylinders H. The clamping members 26 as shown in the figure are cut away upon one side, these portions facing each other for a purpose presently to be described.

Slidably mounted within the member 21 is a short rod 29 having at its lower end, as viewed in the figure, a member 30, the extended and bent down arms 3| of which enter the assemblies for the intake valves 25. of the rod 29 and member 33 the ends of the arms 3| contact with and hold the intake valves 25 in an inoperative position. In the upper positions of this member 30 the arms 3| are disengaged from the intake valves 25 so that these valves 25 can function normally.

In order to operate the rod 23, its upper end is enlarged and over this is placed a diaphragm 32 of rubber or other flexible and impervious material. The diaphragm 32 has its periphery clamped between, portions of the cover member 21 and a concaved plate 33 forminga pressure tight compartment above the diaphragm 32. By admitting air under pressure to the space above the diaphragm 32 the member 30 isiorced down against the pressure 01 a-spring 34 normally resiliently holding the member 30 and rod 29 in their upper positions. By admitting and exhausting air under pressure to and from the space above diaphragm 32 the intake valves may be renderedinoperative or operative thus unloading or loading a the compressor as desired.

To control the admission of air to the space within plate 33 and above the diaphragm 32 any form of regulator such .as the centriiugal.

starting regulator 35 may be employed. As this form of unloader regulator may be of standard form, no further description is thought to be necessary. Through this regulator 35 air under In the lowermost position aoamio pressure may be admitted from a connection 33 from the compressor receiver to a pipe 31 connected to the plate 33 during starting of the compressor.

In addition to the fluid pressure means to move the member 30 downward, a supplemental manual means may be provided. These means may include a rod 33 extending through plate 33 and pressing against the diaphragm 32 and rod 23. A spring 39 normally holds this rod upward so that a head thereon forms a pressure tight seat against the plate 33 when in uppermost position. A handle 4| pivoted to the plate 33 enables the rod 38 to be forced downward to depress the rod 29- and member 30.

I claim:

1. An unloading device tor'compressors having adjacent parallel cylinders, a cylinder head covering the entire end thereof, and discharge valves mounted in said head within an annular discharge passage formed therein, said unloading tacting'with said valves and retaining them individually in place, and unitary means mounted on said head and having integral members extending to and contacting with each of said intake valves whereby said intake valves may be moved simultaneous'ly to inoperative positions,

2. An unloading device for compressors having adjacent parallel cylinders, a cylinder head covering the entire end thereof, a circular partition within said head, and'dlschai'ge valves in said head within a discharge passage on the outside of said partition, said unloading devicecomprising in combination, intake valves centrally disposed in said head within said partition, means to admit air to said intake valves, a cover plate secured to said head for retaining said intake valves in position, and fluid operated means supported in said cover plate for rendering said intake valves inoperative.

t ELLIS NATHAN. 

